Gravel Calculator
Enter the size of the area and the depth to find how much gravel to order.
What this tool does
Multiply length × width × depth to get the volume, then add 10% for settling. A 20 ft × 10 ft bed covered to 3 inches needs about 2.0 cubic yards of gravel. There are 27 cubic feet in a cubic yard. Enter your own measurements above to see the volume, bags and weight.
Calculates the volume of gravel to fill an area at a chosen depth, and adds a waste allowance.
Converts the volume into cubic yards, cubic metres, litres, bags and weight.
How to use it
- Choose feet and inches or metres and centimetres.
- Enter the length, width and depth of the area.
- Adjust the waste allowance, density and bag size if you know them.
- Read the volume to order and the weight.
Why use this calculator
Works out how many cubic yards, cubic metres, bags and tonnes of gravel you need from the length, width and depth of the area, plus an allowance for settling. Ordering gravel is a guess for most people, and being short means a second delivery while ordering too much wastes money and leaves a pile to move. Measuring the area and the depth gives a figure you can take to a supplier.
Why we built it
We built the gravel calculator to give cubic yards, bags and weight with a waste allowance, because gravel is sold in all three. Prepare the base with the concrete calculator and cover beds with the mulch calculator.
For a neighbouring job there is also the Fence Calculator, the BTU Calculator and the Topsoil Calculator.
Handy alongside this: the Paver Calculator.
Who this tool is for
- Homeowners making driveways and paths
- Landscapers ordering aggregate
- Builders preparing a base
When to use it
- Ordering gravel for a driveway, path or patio base.
- Filling a drainage trench or planter.
- Comparing bags with a bulk delivery.
- Checking a quote from a supplier.
How it works
Volume = length × width × depth. With feet and inches: length (ft) × width (ft) × depth (in) ÷ 12 gives cubic feet, and dividing by 27 gives cubic yards. In metric, length (m) × width (m) × depth (cm) ÷ 100 gives cubic metres. The waste allowance multiplies the result by 1 + allowance.
Weight = volume × density. The density used is 1600 kg per cubic metre, a typical figure; it changes with moisture and grade, so ask your supplier. Bags are the volume divided by the bag size printed on the bag, rounded up.
Typical depths: 2-3 inches (5-8 cm) for a path, 4 inches (10 cm) for a driveway top layer and 6 inches (15 cm) or more for a base. Check the advice for your project.
A worked example
These are the values the calculator opens with, so you can see exactly what it does with them. Change any value on the page and the result updates; the figures below come from the same calculation.
| Input | Value |
|---|---|
| Units | Feet and inches |
| Length | 20 |
| Width | 10 |
| Depth | 3 |
| Extra to allow for settling and waste | 10 |
| Density of gravel | 1600 |
| Bag size | 0.5 |
With those inputs, the calculator returns:
- Gravel needed: 2.04 cubic yards (1.56 m³)
- Cubic feet: 55
- Litres: 1,557
- Weight (tonnes): 2.49
- Weight (US tons): 2.75
- Weight (pounds): 5,494
- Bags of 0.5 cubic feet: 110
- Area covered: 200 sq ft
What you give it, and what you get back
| Item | Details |
|---|---|
| Units | Feet and inches, or metres and centimetres. |
| Length, width, depth | The size of the area to cover and the depth of the layer. |
| Waste, density, bag size | Allowance for settling, material density in kg/m³ and bag volume in cubic feet. |
| Output | Cubic yards, cubic metres, litres, weight in tonnes, US tons and pounds, and the number of bags. |
Issues you may run into
| What you see | Why it happens | What to do |
|---|---|---|
| The area is not a rectangle | The calculator multiplies length by width. | Split the area into rectangles and add the results. |
| Order is short | The depth varied or the material settled. | Increase the waste allowance. |
| My supplier uses a different density | Density varies with the product and moisture. | Enter their density. |
| Depth entered in the wrong unit | Depth is in inches or in centimetres. | Check the units setting. |
Assumptions and limitations
- Rectangular areas only.
- Weight depends on the density you enter.
- Bag counts depend on the bag size printed on the product.
Frequently asked questions
How do I calculate how much gravel I need?
Multiply length by width by depth, convert to cubic yards by dividing cubic feet by 27, and add about 10% for settling.
How many tons of gravel do I need?
Convert the volume to cubic yards, then multiply by the density. Gravel is about 1.35 tons per cubic yard at the default density; the calculator shows the weight.
How deep should a gravel driveway be?
Commonly a 4 inch top layer over a base of 4 to 6 inches, depending on the soil and traffic.
How many cubic feet are in a cubic yard?
There are 27 cubic feet in a cubic yard.
Should I add extra?
Yes. 5-10% covers settling and uneven ground.
Is my information sent anywhere?
No. The calculation runs in your browser and nothing leaves the page.
Sources and accuracy
Volume is area times depth converted to cubic yards with NIST-defined factors, and tonnage uses a density the user enters because aggregate density varies by stone type. Standard reference information for aggregate materials is published by the United States Geological Survey.
Figures last checked against the source on . Standards and rates can change — if you are relying on this for something that matters, confirm against the source above. Think a figure is wrong or out of date? Send a correction.